Abstract: Objective To assess the patterns of linkage disequilibrium （LD） of 16 STR loci on X chromosome and investigate the genetic stability. Methods Genomic DNA samples extracted from blood stains from 500 unrelated individuals and 885 lineage members from Eastern Chinese Han population were genotyped through multiplex amplification using IDtyperX-16 kit by our independent research followed by capillary electrophoresis. LD was assessed by PowerMarker v3.25 software and mutation rate of every locus was analyzed. Results LD were not found at the 16 X-STR loci. Allele mutations were observed at 10 loci. Among them, mutation rates of DXS6809 and DXS7132 were both up to 0.004 8. Conclusion When the 16 X-STR loci included in IDtyperX-16 kit were used for parentage testing, product principles can be applied to calculate the likelihood, but mutation should be taken into consideration in the case that the genotypes do not meet the genetic law （especially at DXS6809 and DXS7132）.

Key words: forensic genetics, X chromosome, short tandem repeats, linkage disequilibrium, mutation rate